Insight into Out‐of‐Layer Fluctuations in the Smectic A Stability of 3,5‐Diarylisoxazole Liquid Crystals
作者:Eric S. Sales、Gabriel M. Santos、Richard J. Mandle、Wallison C. Costa、Ivan H. Bechtold、Itamar L. Gonçalves、Vera L. Eifler‐Lima、Aloir A. Merlo
DOI:10.1002/cphc.202000276
日期:2020.7.2
Polar‐terminated 3,5‐diarylisoxazole liquid crystals (ILCs) were synthetized and characterized. ILCs are composed by rigid core 3,5‐diarylisoxazol, alkyl chain and polar‐terminated flexible spacer. Hydroxyl‐, ketal‐ and 1,2‐diol‐terminated ILCs rendered smectic C and A mesophase, while bromine‐terminated ILCs showed smectic A and B mesophase, for monosubstituted and linear ILCs. For branched alkyl
合成并表征了极性封端的3,5-二芳基异恶唑液晶(ILC)。ILC由刚性核心3,5-二芳基异唑,烷基链和极性终止的柔性间隔基组成。对于单取代和线性ILC,羟基,缩酮和1,2-二醇封端的ILC呈现近晶C和A中间相,而溴封端的ILC显示出近晶A和B中间相。对于支链烷基链,检测到单向SmA,对于双取代ILC,未检测到中间相。基于X射线衍射数据和纹理讨论了层外波动(OLF)。OLF取决于溴原子的硬度,通过集体作用产生的氢键以及层之间界面处的构象效应。还获得了定向溴和羟基封端的ILC的近晶翻译顺序参数(TOP)Σ,并将其与OLF相关。对于1,2-二醇封端的ILC,建立了两个SmC亚层,可能与分子内氢键有关,有利于5元和6元形成。